Monodisperse‐porous poly(styrene‐co‐divinylbenzene) beads providing high column efficiency in reversed phase HPLC

A multistage polymerization protocol, the so‐called “modified seeded polymerization,” was developed for the production of monodisperse‐porous poly(styrene‐co‐divinylbenzene) providing high column efficiency as a packing material in reversed phase high performance liquid chromatography (RPLC). In the first stage of the multistage production, uniform polystyrene seed particles, produced by dispersion polymerization, were swollen by an organic agent (i.e., the diluent) and then by a monomer mixture containing styrene and divinylbenzene. The final porous particles were obtained in the monodisperse form by the polymerization of monomer mixture in the seed particles. By the use of a small size seed latex with low molecular weight and by the selection of the appropriate diluent, relatively small monodisperse‐porous particles with suitable pore structure could be achieved. In the reversed phase separation of alkylbenzenes, under isocratic conditions, theoretical plate numbers up to 40,000 plates/m were achieved by using 5.2 μm porous particles, obtained by a toluene‐dibutyl phthalate mixture as the diluent. No significant decrease in the resolution power was observed by the fourfold increase in the mobile phase flow rate. The column efficiency and the resolution observed with 5.2 μm monodisperse‐porous particles were significantly higher with respect to the currently available polymer based packing materials used in the reversed phase HPLC. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 95: 1430–1438, 2005     

A data fusion framework with novel hybrid algorithm for multi-agent Decision Support System for Forest Fire

In this study Forest Fire Decision Support System (FOFDESS) which is a multi-agent Decision Support System for Forest Fire has been presented. Depending on the existing meteorological state and environmental observations, FOFDESS does the fire danger rating by predicting the forest fire and it can also approximate fire spread speed and quickly detect a started fire. Some data fusion algorithms such as Artificial Neural Network (ANN), Naive Bayes Classifier (NBC), Fuzzy Switching (FS) and image processing have been used for these operations in FOFDESS. These algorithms have been brought together by a designed data fusion framework and a novel hybrid algorithm called NABNEF (Naive Bayes Aided Neural-Fuzzy Algorithm) has been improved for fire danger rating in FOFDESS. In this state, FOFDESS is an integrated system which includes the dimensions of prediction, detection and management. As a result of the experiments, it was found out that FOFDESS helped determining the most accurate strategy for fire fighting by producing effective results.     

Active vibration suppression of a flexible structure using sliding mode control

In this paper, sliding mode control (SMC) is designed and applied to an elastic structure to suppress some of its vibration modes. The system is an elastic beam clamped on one end and the designed controller uses only the deflection measurement of the free end. The infinite dimensional mathematical model of the beam is reduced to an ordinary differential equation set to represent the behavior of required modes. Since the states of the finite dimensional model are not physically measurable quantities, an observer is designed to estimate these states by measuring the tip deflection of the beam. The performance of the observer is important because the observed states are used in the SMC design. In this study, by using the output information, an observer is designed and tested to estimate the states of the finite dimensional model of the beam. Then the designed SMC is applied to the experimental beam system which gives satisfactory suppressed vibrations.     

Non-local stabilization of nonlinear systems using switching manifolds

The stabilization of nonlinear systems is considered by reducing the problem to a lower dimensional switching manifold which is made globally attracting. The switching manifold is designed using the stable manifold of the unforced system. The technique is first developed in local case and then in the global situation of nonlinear vector fields on manifolds. The method generalizes the standard L yapunov approach.     

Separation of the protease enzymes of Bacillus licheniformis from the fermentation medium by crossflow ultrafiltration

The separation from fermentation medium of extracellular serine alkaline protease (SAP) enzyme produced by Bacillus licheniformis was investigated using a crossflow ultrafiltration system. SAP was separated from the high molecular weight neutral protease (NP) and amylase (AMY) enzymes and from the low molecular weight organic acids and amino acids in a crossflow ultrafiltration system with 30 000 Da and 10 000 Da MWCO polysulfone membranes, respectively. The effects of transmembrane pressure (TMP), recirculation velocity (v), and initial enzyme concentration (C_E) on the permeate flux, on the activities of SAP, NP and AMY enzymes, and on the recovery of SAP were investigated. High permeate flux was obtained at high recirculation velocity and TMP, but at low initial enzyme concentration. SAP enzyme recovery and activity measured in the system also showed alterations with hydrodynamic conditions. The best operation conditions for the separation of SAP from NP and AMY were TMP = 20 kPa, v = 0.50 ms⁻¹ and C_E = 0.28 gdm⁻³. The separation of SAP from the organic and amino acids was best performed at TMP = 100 kPa, v = 0.33 ms⁻¹ and C_E = 0.40 gdm⁻³. © 2000 Society of Chemical Industry     

Magnesite concentration technology and caustic – calcined product from Turkish magnesite middlings by calcination and magnetic separation

This paper deals with the current magnesite concentration technology and upgrading studies in Turkey, which is the second biggest magnesite and third biggest sinter magnesia producer in the world. Magnesite heat treatment and magnetic separation fundamentals are also covered. This study aims to concentrate magnesite middlings containing the silica/iron impurities from Kütahya, Turkey, by calcination and dry magnetic separation. Final calcined MgCO₃ product contains 89.57% MgO, 0.96% SiO₂, 0.43% Fe₂O₃, 2.35% CaO and 6.64% loss of ignition. The optimum particle size was determined at ?8 + 0.5 mm at 1000°C. Final product is saleable for industrial applications (i.e., soil decontamination, panels, fertilizers, animal nutrition, abrasives).     

Computational analysis of hydrogen storage capacity using process parameters for three different metal hydride materials

In this study, hydrogen storage capacity were analyzed by considering hydrogen absorption test rig depending on some reactor design parameters such as metal hydride particle size, having fins at the tank, hydrogen inlet pressure, inlet radius of the tank, coolant temperature, general convective heat transfer coefficient and wall thickness of the tank. In the specified design parameters of the hydrogen storage system we put these in COMSOL Multiphysics 5.1 software to obtain some approaches in the large scale. All parameters were analyzed using three different metal hydrides of the MmNi_4,6Al_0,4, LaNi_4.75Al_0.25 and LaNi₅. Some parameters like temperature distribution inside the tank, amount of the hydrogen mass to be stored in the tank, the time durations of them and the variations of the equilibrium pressure of the system were optimized.     

Fuzzy diffusion filter with extended neighborhood

Anisotropic diffusion filters, which are motivated from heat diffusion between mediums, have become a widely used technique in the field of image processing. In the initial proposals of anisotropic diffusion filters, 4-neighborhood values with diffusivity functions are computed independently for each spatial location because of numerical approximation. However, anisotropic diffusion filters could not be used in real-time image and video processing applications because they need diffusivity parameters, which must be specified by users in every sampling period. In this study, a fuzzy adaptive diffusion filter using extended neighborhood without diffusivity functions has been developed. The fuzzy adaptive diffusion filter does not require any parameter chosen by user and therefore they could be employed in real-time applications. In the fuzzy adaptive diffusion filter, a similarity transformation by means of relation matrix and fuzzy logic is carried out. Accordingly, the similarity image, output of transformation, is directly used as a heat diffusion coefficient in the diffusion filter. Results show that the fuzzy adaptive diffusion filter is very efficient for removing noise in image while preserving edges.